We were able using a sound and reliable Elisa assay to identify the RIAO cut point (≥ 3.35 μg/ml) on the AUC curve as a biomarker of greater β cell damage in children with obesity and high cardiometabolic risk (severe comorbidities: dyslipidemia, fasting hyperglycemia, fatty liver disease elevation) or functional alteration of β cells (resistance to insulin HOMA and fasting C peptide), with a sensitivity of 0.93 and specificity of 0.79. The gene discussed is INS; the disease is metabolic syndrome.